The continuing need for more oil at lower operating costs has motivated inventors to develop pipe handling schemes and equipment. Various types of pipe handling or pipe racking apparatus for moving pipe sections between a storage array and the drill string of an oilwell or derrick have been disclosed U.S. Pat. No. 2,416,815 by I. X. Calhoun describes one such mechanism. Others have included control schemes or suggested methods where some of these operations could be automated. U.S. Pat. No. 3,800,962 by J. E. Ham is an example.
Normally, a drilling crew includes a person known as the "derrick man" or "tower man" who stands on a working platform (sometimes called the fourble board) high on the drilling rig. After the lower end of a pipe section has been disconnected from the drill string and properly placed in storage by a "floor operator", the tower man manually unlatches the pipe elevator from the upper end of the pipe section, removes the top of the pipe section from the pipe elevator, and locates the pipe section in the derrick for storage.
After a new drill bit has been installed, the drill string is reconstructed by recoupling the sections of pipe stored within the derrick. In this case, the derrick draw works is actuated to raise the pipe elevator until it is at the proper elevation for attaching a section of pipe. In this situation, the tower man manually pulls the upper end of a section of pipe from the storage array and loads the upper end into the pipe elevator. Once loaded into the pipe elevator, the pipe section is lifted off the tower floor and joined into the drill string attached to the drill bit. Those familiar with these duties of tower man realize that it is somewhat dangerous and fatiguing and not especially suitable for speedy operation.